(1) Field of the Invention
The present invention relates to a novel and advantageous additive to fuels for motor vehicles and more particularly to a chemical scavenger additive for fuels containing an anti-knocking lead compound, and to a method of using such additive as scavenger for such leaded fuels.
(2) Description of the Prior Art
To increase the octane number of gasoline alkyl lead anti-knocking fluids are added in amounts up to 4.23 g. of lead per gallon of fuel. This amount of lead corresponds to 4 cc. of tetra-ethyl lead, the most widely used commercial anti-knocking agent. Mixtures of tetra-ethyl lead with tetra-methyl lead or of ethyl trimethyl lead, di-ethyl dimethyl lead and triethyl methyl lead in addition to tetra-ethyl lead and tetra-methyl lead have also been added commercially to gasoline as anti-knocking agents. Such leaded gasoline has proved to yield a gasoline with a high octane number in the most economical manner. However, such gasoline has the disadvantage that small amounts of lead are deposited on combustion in the engine and cause severe damage thereto. Therefore, so-called scavenger additives have been added to the leaded gasoline in order to inhibit such deposit formation. Especially suitable for their scavenger action have proved to be 1,2-ethylene dibromide and mixtures of ethylene dibromide with ethylene dichloride. Large amounts of these ethylene halides are now manufactured for this purpose.
Recently it was found that ethylene dibromide causes cancer in laboratory animals when fed to them in large amounts. Thus it may represent a major health hazard not only to the gasoline station attendants but also to the workers in chemical plants producing such scavenger additives.